<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            font-family: "Arial", "微软雅黑";
        }

        ul,
        li {
            list-style: none;
        }

        .bbs {
            margin: 0 auto;
            width: 600px;
            position: relative;
        }

        header {
            padding: 5px 0;
            border-bottom: 1px solid #cecece;
        }

        header span {
            display: inline-block;
            width: 220px;
            height: 50px;
            color: #fff;
            background: #009966;
            font-size: 18px;
            font-weight: bold;
            text-align: center;
            line-height: 50px;
            border-radius: 8px;
            cursor: pointer;
        }

        .post {
            position: absolute;
            background: #ffffff;
            border: 1px #cccccc solid;
            width: 500px;
            left: 65px;
            top: 70px;
            padding: 10px;
            font-size: 14px;
            z-index: 999999;
            display: none;
        }

        .post .title {
            width: 450px;
            height: 30px;
            line-height: 30px;
            display: block;
            border: 1px #cecece solid;
            margin-bottom: 10px;
        }

        .post select {
            width: 200px;
            height: 30px;
        }

        .post .content {
            width: 450px;
            height: 200px;
            display: block;
            margin: 10px 0;
            border: 1px #cecece solid;
        }

        .post .btn {
            width: 160px;
            height: 35px;
            color: #fff;
            background: #009966;
            border: none;
            font-size: 14px;
            font-weight: bold;
            text-align: center;
            line-height: 35px;
            border-radius: 8px;
            cursor: pointer;
        }

        .bbs section ul li {
            padding: 10px 0;
            border-bottom: 1px #999999 dashed;
            overflow: hidden;
        }

        .bbs section ul li div {
            float: left;
            width: 60px;
            margin-right: 10px;
        }

        .bbs section ul li div img {
            border-radius: 50%;
            width: 60px;
        }

        .bbs section ul li h1 {
            float: left;
            width: 520px;
            font-size: 16px;
            line-height: 35px;
        }

        .bbs section ul li p {
            color: #666666;
            line-height: 25px;
            font-size: 12px;
        }

        .bbs section ul li p span {
            padding-right: 20px;
        }
    </style>
</head>

<body>
    <div class="bbs">
        <header><span onclick="iWantPost()">我要发帖</span></header>
        <section>
            <ul>
                <!--
                <li>
                   <div>
                       <img src="images/tou01.jpg" alt="">
                   </div>
                   <h1>如何学习前端Web开发课程</h1>
                   <p><span>版块：新课来了</span><span>发表时间：2019-10-13 10:9</span></p>
                </li>
                -->
            </ul>
        </section>
        <div class="post" id="post1">
            <input id="title" placeholder="请输入标题（1-50个字符）">
            所属版块：<select>
                <option>请选择版块</option>
                <option>电子书籍</option>
                <option>新课来了</option>
                <option>新手报到</option>
                <option>职业规划</option>
            </select>
            <textarea class="content"></textarea>
            <input class="btn" value="发布" onclick="post()">
        </div>
    </div>
</body>

</html>

<script>

    function iWantPost() {
        document.getElementById("post1").style.display = "block";
    }

    function headPortrait() {
        //使用数组保存发帖者的头像
        var head = new Array("img/01.png", "img/02.png", "img/03.png", "img/04.png");
        //生成 0 到 数组长度之间的随机数
        var n = parseInt(Math.random() * 4);
        return head[n];
    }

    function post() {
        document.getElementById("post1").style.display = "none";
        /* 创建节点 */
        var ul = document.getElementsByTagName("ul")[0];
        var li = document.createElement("li");
        var div = document.createElement("div");
        var img = document.createElement("img");
        var h1 = document.createElement("h1");
        var p = document.createElement("p");
        var span = document.createElement("span");

        ul.appendChild(li);
        li.className = ".bbs section ul li";

        li.appendChild(div);
        div.className = ".bbs section ul li div";

        // 插入头像
        div.appendChild(img);
        img.className = ".bbs section ul li div img";
        img.src = "" + headPortrait();

        // 插入标题
        li.appendChild(h1);
        h1.className = ".bbs section ul li h1";
        h1.innerHTML = document.getElementById("title").value;

        // 插入板块
        li.appendChild(p);
        p.className = ".bbs section ul li p";
        p.innerHTML = "版块：" + document.getElementsByTagName("select")[0].value;

        // 插入时间
        p.appendChild(span);
        span.className = ".bbs section ul li p span";

        var today = new Date();
        var year = today.getFullYear();
        var month = today.getMonth() + 1;
        var day = today.getDate();
        var hour = today.getHours();
        var minute = today.getMinutes();
        var second = today.getSeconds();

        span.innerHTML = "发表时间：" + year + "-" + month + "-" + day + "&nbsp;" + hour + ":" + minute + ":" + second;

        document.getElementById("title").value = "";
        document.getElementsByTagName("select")[0].value = "";
        ul.insertBefore(li, ul.firstElementChild);
    }
</script>